Electrically driven striking tool



Dec. 11, 1934. R. DEDERER 1,984,256

ELECTRICALLY DRIVEN STRIKING TOOL Filed'Dec. 22, 1955 I z 1 A -2 0/ g ii c b? a b 5 1 f/ T3 3 ,2 f P f I v Patented Dec. 11, 1934 UNITED STATESPATENT OFFICE Richard Dederer, Stuttgart, Germany, assignor to Kapital &Industriewerte A. G Basel, Switzerland Application December 22, 1933,Serial No. 703,651

4 Claims.

Electrically driven striking tools controlled by means of plane camscomprise one or more striking bodies, which act upon a resilient ram.

According to the present invention the cross section of each strikingbody is in the shape of a sector of a circle, so that all the strikingbodies unite together to form a cylinder coaxial with the ram.

One form of construction of the invention is illustrated by way ofexample in the accompanying drawing, in which t Figure 1 shows thestriking tool in longitudinal section through the hammer casing,together with the driving means.

Figure 2 is a cross section showing the arrangement of the hammers, and

Figure 3 is a diagrammatic view of the individual hammer as it leavesthe plane cam.

In a casing a. are slidably mounted four hammers b, c, d and e, in sucha way that their segmental cross sections together form a circle, asindicated in Fig. 2. Each hammer therefore has three guiding surfaces,two of which serve at the same time for guiding the two adjacenthammers. The, hammers are longitudinally slidable independently ofoneanother, and are pressed slowly by a plane cam g, in the sequenceindicated, against a spring 0, and, after reaching their highest point,are liberated so that they spring back on to the ram of the tool withoutany obstruction. This unhampered blow is obtained by the quick yieldingof a pendulum member h (Fig. 3), rockably arranged on the hammer, with aguiding roller t. In this figure the operation is diagrammaticallyillustrated, the cam n moving in the direction of the arrow. The toolram rests upon an antagonistic spring m, which has to take up the blowswhen the tool is working idly, an abutment pin s limiting the recoil ofthe ram. The wheel g of the plane cam is driven by means oftoothed-wheel counter-shaft gearing p, i, is from an electric motor I.The motor itself is switched on and off by means of a switch lodged in aknown manner in the interior of a handle it. Since the ram 1 forms theradial guide for the controlling cam g, a rotation of the tool ram 1takes place simultaneously with each blow. This rotation may be effectedpositively by providing the ram with a tappet in the form of a wedge wor similar auxiliary means slidably Germany November 23, 1932 guided ina slot 12 of the control cam, or conversely. Balls 1' serve for takingup the spring pressure.

Having now particularly described and ascertained the nature of my saidinvention and 5 in what manner the same is to be performed, I declarethat what I claim is:-

1. In an electrically driven striking tool, individual striking bodies,a cam disc for controlling the striking bodies, and a ram carryng thetool itself, the striking bodies being so arranged as to fall upon theram as the cam disc rotates,

' each striking body having a cross-section in the form of a sector of'a circle and all the striking bodies together forming a cylinder 00-axial with the ram.

2. In an electrically driven striking tool, individual striking bodies,a cam disc for controlling the striking bodies, and a ram carrying thetool itself, the striking bodies being so arranged as to fall upon theram as the cam disc rotates, each striking body having a cross-sectionin the form of a sector of a circle andall the striking bodies togetherforming a cylinder coaxial with the ram, the cam disc being formed witha bore, 5 and the ram fitting into this bore in such a way that when thecam disc rotates the ram is rotatedwith it.

3. In an electrically driven striking tool, individual striking bodies,a cam disc for controlling thestriking bodies, a ram carrying the toolitself, the striking bodies being so arranged as to fall upon the ram asthe cam disc rotates, each striking body having a cross-section in theform of a sector of a circle and all the striking 5 bodies togetherforming a cylinder coaxial with the ram, and a radial coupling betweenthe cam disc and the ram.

4. In an electrically driven striking tool, individual striking bodies,a cam disc for controlling the striking bodies, a ram carrying the toolitself, the striking bodies being so arranged as to fall upon the ram asthe cam disc rotates, each striking body having a cross-section in theform of a sector of a circle and all the striking bodies togetherforming a cylinder coaxial with the ram, a pendulum member on eachstriking body and a roller on each pendulum member, the said rollerbearing upon the cam disc.

RICHARD DEDERER.

